Cellular Telephone System

  Cellular system  accommodate a large number of users over a large geographic area, within a limited frequency spectrum and provide high quality service that is often comparable to that of the land line telephone system.

 High capacity is achieved by limiting the coverage area of each base station transmitter to a small geographic area called ‘cell’ so that  another base station reuses the  same radio channels  located some distance away.

 A sophisticated switching called a handoff enables a call to proceed uninterrupted, when the user moves from one cell to another.  A wireless connection  is provided by the system  to the PSTN for any user location within the radio range of the system.

Working of Cellular telephone system

Cellular Telephone system consists of three sub-systems they are

1.            Mobile unit

2.            Cell site

3.            Mobile Telephone Switching Office

All these three sub-stations are joined using high-speed data links.

Mobile unit:

This subsystem encompasses a control unit, a transceiver to transmit an receive signals and an antenna to radiate signals.

Cell Site:

This part of the cellular system  acts as an interface between mobile telephone switching center and the mobile unit. It encompasses all the elements of a mobile unit  in addition, it has radio cabinets , power plant and data terminals.  

Mobile Telephone Switching Office:

The MTSO is the most important cooperating element for all cell sites in the cellular system. It has a cellular processor and cellular switch The switching office is linked to telephone company zone offices and its main function is to control call processing and manage billing activities. The cellular switch is used to connect one mobile subscriber to another mobile subscriber in the cellular mobile system. The voice trunks used by MTSO are similar to voice trunks used by telephone company zone offices. In addition, it has data links that imparts administration links between the processor and the cell sites and between processor and switch.